


Submerged

by Ausp_ice



Series: Submergence [2]
Category: Detroit: Become Human (Video Game)
Genre: Alternate Universe - Merpeople, Anal Sex, Biting, Bottom Connor (Detroit: Become Human), Creampie, Human Connor (Detroit: Become Human), Knotting, M/M, Mer Nines, Mute Connor (Detroit: Become Human), Non-Human Genitalia, Nonverbal Communication, Teratophilia, Top Upgraded Connor | RK900, Trans Connor (Detroit: Become Human), Underwater Sex
Language: English
Status: Completed
Published: 2020-10-26
Updated: 2020-10-26
Packaged: 2021-03-08 17:42:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,858
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27200612
Author URL: https://archiveofourown.org/users/Ausp_ice/pseuds/Ausp_ice
Summary: Their first time in the endless sea.
Relationships: Connor/Upgraded Connor | RK900
Series: Submergence [2]
Series URL: https://archiveofourown.org/series/1985711
Comments: 8
Kudos: 55





	Submerged

**Author's Note:**

> Well, here's the mer smut I've been wanting to write for ages. The "Sex in Water" prompt seemed like an excellent opportunity haha
> 
> Art is posted on [Twitter](https://twitter.com/Au_spice/status/1320530308748382208?s=20).

* * *

Their first time under the sea is both similar and different to their escapades before—whether on Connor's mattress, or in the pool.

It is certainly different from when Nines takes a fully human form—but even for their other aquatic experiences, Connor has not, before, been able to breathe underwater. 

Only a week passes before it happens, a week Nines spends helping Connor adjust to a more aquatic life. Figuring out food was certainly trying, given that humans do not enjoy raw, unprepared fish. Connor ends up sticking mostly to seaweed. 

The transformation will elucidate the change in his diet—while the first shift was minute, its effects will continue to grow. And soon, he will… 

A touch on Nines's face turns his focus back to the present. Connor is watching him, smiling slightly, hair floating in a halo around his face. The filaments of light filtering through the ocean above spill across his features. He is laying down on a large boulder, smoothed by the sea, arms wrapped around Nines, who lays above him. He has been divested of his clothes; they are pinned under a nearby rock to keep them from drifting away. The two of them are skin-to-scale—though Nines is careful to ensure Connor's delicate human flesh is primarily exposed only to Nines's softer underbelly. 

Connor lifts one hand away from Nines's back, forming one of those finger symbols he uses.  _ Okay?  _

Nines makes a few clicks and calls that would mean  _ I'm alright  _ in his own language, but of course Connor cannot understand. So Nines lifts his own hand, copying Connor's symbol.  _ Okay.  _

Connor smiles, lifting a hand to Nines's face and kissing the corner of his mouth. Nines turns his head to seal their lips together, the taste of Connor clear through the ocean's saltiness. 

Neither of them are truly able to speak a human language, but Connor has never let that stop him. Somehow, they were able to connect in a shared silence, and Nines—Nines is filled with a feeling he can only identify as adoration. That Connor helped him, that Connor stayed with him, that Connor bridged the gap of communication between them. 

Nines makes a chirring sound, fingers pressed over Connor's heart. His other hand he hooks around the back of Connor's neck, pressing them closer as he prods his tongue into the human's mouth. 

A stream of bubbles escape Connor's lips as he parts them to let Nines in; they tickle him, in a way. But he is more concerned with the way Connor arches his back as Nines tangles his tongue with Connor's, pressing deep.

The human was surprised at the difference in anatomy the first time they kissed. To be fair, Nines's tongue is much longer than Connor's, and his saliva is much more viscous to better last in the ocean. 

Connor's hand lands on Nines's back, fingers digging in right at where his spine transitions to his dorsal fin. He lets out a rumbling set of clicks, pressing himself closer. 

He can feel his arousal growing, his slit growing slick with viscous fluid. Nines parts their lips, and a string of Nines's saliva drifts between them before melting into the sea. He can see the way the light of his bioluminescence flickers on Connor's face, growing ever brighter. The human's pupils are blown wide, and his lips, slightly parted, are swollen with Nines's attention. 

Nines proceeds to lower his head once more, but this time to Connor's neck, nibbling at the soft flesh with his sharp teeth. He does not break skin, not yet, but still Connor shivers under him, and— 

Nines jolts as Connor slides a hand down to his slit, pressing clever fingers inside. He presses his forehead against the human’s shoulder, trying to keep most of his body still even as his expansive tail sweeps across the sand behind him. 

There's a soothing touch on his back, gently pressing down from his neck to his spine to his dorsal fin again and again. Then, a pressure on his temple—a kiss from the human, it must be—and Nines rumbles, pleased.

Connor works Nines's slit expertly, coaxing out his member. Nines shivers as his heated length hits the chill ocean water, but Connor quickly lifts his legs around Nines's back and guides it towards his lower entrance. 

While the human has his own slit, one that even lubricates on its own, Connor curiously prefers the other entrance. Nines has taken him with both—and each are enjoyable in their own way.

He lifts his face up to look at Connor, fins spreading and flattening. The human's eyes are hooded, and he nods quickly, hair drifting too slowly to follow his movements exactly. 

So Nines presses in slowly, starting only with his tip, the way made easy by his slick. He resists the urge to lose himself in the velvet heat, to bury his face in Connor's shoulder once more, so that he can see the human's eyes flutter shut, can see the way his mouth parts in pleasure. 

The human was enamored with Nines's phallus the first time he saw it, Nines recalls. It is pointed and thinner at the tip, though slightly larger at the head, widening down its ridged, curved shaft to a knot at the base, not to mention bioluminescent with its own glow. It is coated with a thickly viscous slick—were Nines human, Connor would have to prepare much more thoroughly before engaging in such activities, but like this… Nines only has to be patient. 

Nines stops when he feels too much resistance, slightly before he can fit the head of his member inside. Connor has his eyes closed, gills at his neck fluttering as he grips Nines's back. 

He waits until Connor taps him on the arm, and then he presses in further—until the head pops in, and Connor jerks, gills flaring, jaw dropping. Nines leans in to press his lips to Connor's jaw, rumbling gently as the tight ring of muscle clenches around Nines's member. 

Connor turns his head to kiss Nines, hand on the back of Nines's neck to guide him to Connor's lips. Before long, Connor taps him on the arm again, and Nines presses even deeper, feeling every ridge push into that wonderful heat. Connor's hands grasp at Nines's back as he pushes further, onto the knot and deeper, until finally Nines is pressed flush against Connor's body. 

The human is heaving, gills fluttering as he grips Nines's back, eyes scrunched tight. The heat around Nines's member clenches him so, so wonderfully, and Nines mouths at Connor's jaw, his shoulder. The warm tightness is maddening, but Nines is patient. He will wait until the human is ready. 

Eventually, Connor relaxes—as much as he can while being impaled on Nines's length—and lifts up Nines's face with a hand on his cheek. He nods and draws Nines to his lips, and that is when Nines pulls out slowly, every ridge catching against the human's rim. Connor's mouth parts in pleasure, and Nines takes the opportunity to plunge his tongue inside Connor's mouth yet again. 

He presses his hips into that wonderful heat once more, and Connor arches into him, legs squeezing Nines's hips as if to push him in even further. Then out, then in, a steady rhythm of movement. 

It is quiet in the sea—but they are loud, in a way. Connor in the way he pushes his hips up to meet Nines's thrusts, in the way he kisses Nines desperately, gills flaring and shimmering with the beginnings of luminescence. Nines in the way that he ruts into his human, tail whipping being him, fins flaring, bioluminescence flickering. 

Their kisses grow sloppy as Nines loses himself in his pleasure, clinging to Connor's nape and back. He tastes blood as his teeth nick Connor's lips, and he moves to press his tongue against Connor's gills. Connor jerks, back arching, head thrown back, and he is silent but Nines can hear him, hear his pleasure and desire and—and Nines responds, sinking his teeth into the soft flesh of Connor's shoulder, forcing himself deep, deep into Connor's entrance. The knot catches on Connor's rim, and then Nines is coming, filling his mate, his everything. Connor clings to Nines tightly, shuddering as his own pleasure reaches its peak, clenching around Nines's length. 

Nines unlatches his teeth from Connor's flesh, licking it gently as it rapidly heals over. He lifts himself up to look at his mate, and finds a contentedly dazed expression on Connor's face. 

The human smiles, and Nines feels all his fins flutter. Connor smiles even wider at that, and he lifts two fingers to one of Nines's hearts—the one on his left side, a little higher than the one on his right, where Connor slides his fingers to next. Then to his own.

Nines doesn't know if this has a verbal meaning. Perhaps it means that their hearts are together. Or that they are each other's hearts. Whatever it means, Nines knows that it makes him flicker with a strange emotion, and he—he repeats the action, his hearts to Connor's, before he links their hands and pulls them aside so that Nines can lay down on Connor's chest, closing his eyes and savoring the warm pleasure in his bones as he continues to fill his mate. 

Connor lifts a hand to his hair, gently pressing his fingers against the scalp and dragging them down his neck, his back, the edge of his fins. And again, and again… Nines gives a pleased chirr, tail swishing absentmindedly behind him as he sinks into a mind-numbing comfort. 

The human must grow tired at some point, because he soon transitions to just holding Nines close. Time passes, but they feel timeless here in the twilight of the ocean. Eventually, Nines's knot deflates, and he slips out as he lifts himself up. Connor makes a face as the ridges catch on his rim, as Nines's length slides out of the human and back into his slit.

Nines observes his own spend leaking from Connor's hole—a viscous, bioluminescent substance that drips out slowly in strings caught by the ambient ocean current. Nines rubs a hand across Connor's belly, clicking softly. In the dim twilight of the ocean, he can see the glow within. 

Connor shivers, watching Nines watch him, face flushed pink. Nines lifts his hand away, moving it to lift up a thigh and kiss the soft skin there before pulling himself up on the stone next to his mate. He lifts his hand to Connor's face, and the human turns his head slightly to kiss Nines's palm. 

It makes his bioluminescence flare brightly for a moment, and Connor grins. He wraps an arm around Nines's waist, pulling them closer, enough for them to press their foreheads together. Connor touches Nines's hearts again, and then he tucks his head under Nines's chin, closing his eyes. 

Nines wraps a hand around Connor's head, and after a few seconds—he, too, closes his eyes and lets himself drift into satisfied sleepiness. 

**Author's Note:**

> They just love each other a lot.
> 
> Thanks for reading! 
> 
> Check me out on social media: [](https://www.deviantart.com/ausp-ice) | [](https://ausp-ice.tumblr.com) | [](https://twitter.com/Ausp_ice) / [NSFW](https://twitter.com/Au_spice) | [](https://www.instagram.com/ausp.icium)
> 
> I'm also in [Detroit: New ERA](https://discord.gg/GqvNzUm) server! I have my own channel if you'd like to yell at me or just talk.


End file.
